This invention relates to the general field of deposition coating of articles and more specifically relates to the vacuum evaporation or sputtering techniques for deposit of a particular metal alloy in a thin film on an article substrate.
Vacuum evaporation and sputtering techniques have been utilized to a substantial extent in the forming of relatively thin film metal coatings on substrates comprising articles having substantial decorative function. These techniques of depositing a thin film coating of a metal alloy to provide a bright, metallic surface finish have found substantial utilization in the automotive field in the coating of plastic components incorporated in the decorative portions of automotive vehicles. Utilization of such film coating techniques is not limited to the automotive industry nor are they limited to decorative articles. Many articles may be advantageously coated with a protective layer of a suitable metal alloy for both functional and decorative purposes.
In addition to obtaining the particularly pleasing decorative effect, the vacuum evaporation and sputter deposition techniques enable forming of a thin film on plastic parts to enhance their durability in many functional and utilitarian aspects. For example, many of the components formed from plastic and incorporated in automotive vehicles require a coating that not only functions for the decorative aesthetic purposes, but will also have particularly advantageous characteristics for abrasion resistance, resistance to discolorations or degradation as a consequence of ultraviolet radiation, resistance to corrosion effects and to also accommodate mechanical stresses that are induced by thermal differences.
Metal alloys have been developed for this specific purpose of effecting vacuum evaporation and sputter deposition of thin film coatings on plastic substrates as well as other materials. The metal alloys heretofore utilized in such thin film deposition techniques comprise a chromium base and include a substantial percentage component of iron. Chromium is the elemental material which imparts the desirable characteristics of color, brightness and hardness in an attempt to achieve the functional and utilitarian advantages of resistance to abrasion and corrosion.